To
make your own bandgun ammo, you will need some surgical
tubing 1/4" inner diameter with an outside wall
1/16th" thick. Cut a section long enough to match
your existing ammo with a one-inch overlap of the
rubber ends. One side should be cut diagonally.

Slide
the straight-cut end of the rubber tube over an awl,
phillips-head screwdriver, or something else of that
nature. Now roll the end down over itself, making
sure to roll it back enough so you can roll an inch's
worth over material over the other end.

Holding
the rolled end in place so that it doesn't snap back
into it's original unrolled form, slide it off the
awl and put the tip of the diagonally-cut end into
the rolled end. Now roll the flat-cut end down over
the diagonally-cut end, creating an overlap that should
hold itself in place.

This
now needs to be reinforced so that the diagonally-cut
end doesn't slip out of the other end when pulled.
Tighten two zip ties around the overlapping part,
clip off most of the excess zip tie. Now wrap some
duct tape over this. The duct tape will halp to keep
the zip ties from coming apart, but more importantly,
it will keep the band from being damaged by the metal
muzzle it is stretched over again and again. Use a
bright color of duct tape so that you can easily find
the band after you fire it. I usually use white, bright
blue, or hunter orange tape.

*An
idea that was posed to me, in effort to help the band
fly straighter, is to put about a teaspoon of fine
sand into the rubber tubing before coupling it. This,
theoretically, disperses as the band spins through
the air, and helps it to fly straighter. I've not
done this myself, but some people have found it effective.